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| author | Joseph Myers <joseph@codesourcery.com> | 2018-02-15 20:58:16 +0000 |
|---|---|---|
| committer | Fangrui Song <maskray@google.com> | 2021-11-19 13:20:26 -0800 |
| commit | d7c1214f4d417119c4cca5c36c2adfc4d83be8fc (patch) | |
| tree | a6adef5fb4201447a4c565d9989d2e0094919872 | |
| parent | aac0d8a9a3a1ffbfd105de339c8653f39fc5ef17 (diff) | |
| download | glibc-d7c1214f4d417119c4cca5c36c2adfc4d83be8fc.tar.gz | |
Use libc_hidden_* for fputs (bug 15105).
Among other localplt test failures when building with -Os, there are
libc.so PLT references for fputs. fputs calls normally get redirected
to _IO_fputs by a macro in include/stdio.h (and _IO_fputs in turn uses
libc_hidden_proto), but GCC can convert an fprintf call with a
constant string argument into an fputs call, which of course is then
unaffected by the macro redirection. (I don't know why this issue
only appears with -Os.)
This patch duly adds a use of libc_hidden_proto for fputs. I see no
obvious reason why the fputs macro redirection is needed at all, but
this patch does not change it.
Tested for x86_64 (both that it removes this particular localplt
failure for -Os - but other such failures remain so the bug can't yet
be closed - and that the testsuite continues to pass without -Os).
[BZ #15105]
* include/stdio.h [!_ISOMAC && IS_IN (libc)] (fputs): Use
libc_hidden_proto.
* libio/iofputs.c (fputs): Use libc_hidden_weak.
(cherry picked from commit 499b315324519f8deb5b42a143a76319934a3ab0)
| -rw-r--r-- | include/stdio.h | 4 | ||||
| -rw-r--r-- | libio/iofputs.c | 1 |
2 files changed, 5 insertions, 0 deletions
diff --git a/include/stdio.h b/include/stdio.h index f1e987ae5e..6759ed3fb1 100644 --- a/include/stdio.h +++ b/include/stdio.h @@ -135,6 +135,10 @@ extern int _IO_new_fclose (_IO_FILE*); # define fclose(fp) _IO_new_fclose (fp) extern int _IO_fputs (const char*, _IO_FILE*); libc_hidden_proto (_IO_fputs) +/* The compiler may optimize calls to fprintf into calls to fputs. + Use libc_hidden_proto to ensure that those calls, not redirected by + the fputs macro, also do not go through the PLT. */ +libc_hidden_proto (fputs) # define fputs(str, fp) _IO_fputs (str, fp) extern int _IO_new_fsetpos (_IO_FILE *, const _IO_fpos_t *); # define fsetpos(fp, posp) _IO_new_fsetpos (fp, posp) diff --git a/libio/iofputs.c b/libio/iofputs.c index b4fbeb5e60..176e9ed281 100644 --- a/libio/iofputs.c +++ b/libio/iofputs.c @@ -43,6 +43,7 @@ _IO_fputs (const char *str, _IO_FILE *fp) libc_hidden_def (_IO_fputs) weak_alias (_IO_fputs, fputs) +libc_hidden_weak (fputs) # ifndef _IO_MTSAFE_IO strong_alias (_IO_fputs, __fputs_unlocked) |